TREM2 and Alzheimer disease: Modifications of the concentrations of several cytokines (160–164) and other inflammatory biomarkers associated with either microglia—e.g., soluble TREM2 (sTREM2), monocyte chemoattractant protein-1 (MCP-1), and YKL-40 (165–168)—or astroglia, e.g., YKL-40 (161), are extensively investigated in AD patients.